The present invention relates to a device for transporting workpieces. More particularly it relates to a device for transporting workpieces with a transporting path system for transporting wagons, wherein the transporting wagons have their own traveling mechanisms, and means is provided for controlling the travelling mechanisms and possibly the traveling paths of the transporting wagons. In a known device of this generic type the sensors provided for monitoring the system conformity are directed toward the running surface of the transporting path carrier and, via control means which are arranged downstream, render the blocking of the traveling mechanism ineffective as soon as and as long as they determine the presence of the running surface and a predetermined vertical distance relative to the latter. However, this arrangement is not completely assured because the sensors also cancel the blocking of the traveling mechanism when the transporting wagon is located outside the transporting path on a surface which corresponds to the running surface of the transporting path carrier with respect to material and surface characteristics.